This is part of the Semicolon&Sons Code Diary - consisting of lessons learned on the job. You're in the networking category.
Last Updated: 2024-04-19
NAT is used to map a range of private addresses (say, 192.168.1.X) to and from a (usually) smaller set of public address, thereby reducing the demand for routable, public IP space.
The IP header is actually modified on the fly by the NAT device to change the source and/or destination IP address.